Application status and introduction path of silicon carbide in new energy vehicles

1 Use the advantages

1.1 Helping New Energy Vehicles to Improve Acceleration

The acceleration performance of new energy vehicles is closely related to the maximum power and maximum torque output by the power system. Silicon carbide (SiC) technology allows the drive motor to withstand greater input power at low speeds, and is not afraid of thermal effects and power losses caused by excessive current. This means that when the vehicle starts, the drive motor can output more torque and enhance the acceleration ability. Tesla has released the world’s fastest mass-produced model at this stage, which can accelerate from 0 to 100 km in 2.1 s, surpassing Bugatti’s speed; while BYD Han uses SiC modules, the output power can reach 200 kW, 0 to 100 km Acceleration is only 3.9 s[1-2].

1.2 Help new energy vehicles reduce system costs

Although the cost of SiC devices is slightly higher than that of silicon-based devices, the use of SiC devices has achieved a substantial reduction in battery costs and an increase in cruising range, thereby effectively reducing the cost of the entire vehicle. The data shows that the (90-350) kW drive inverter using SiC MOSFET in new energy vehicles will increase the cost of using SiC devices by 75-200 US dollars (1 US dollar is about 6.5 yuan), but from batteries, passive elements The cost savings of components and cooling systems range from $525 to $850, and the systemic cost is significantly reduced. Under the same mileage, a single vehicle using a SiC inverter can save at least $200.

  

Application status and introduction path of silicon carbide in new energy vehicles

Figure 1 Source of revenue from the use of SiC products in new energy vehicles: the author organizes it by himself

1.3 Helping new energy vehicles increase their cruising range

SiC devices reduce losses through the two dimensions of conduction/switching, thereby achieving the purpose of increasing the cruising range of electric vehicles. The forbidden band width of SiC (3.3eV) is much higher than that of Si (1.1eV), which can achieve high-concentration doping, resulting in a significant reduction in the width of the drift region. When the SiC MOS device is turned on, the forward voltage drop and conduction loss are less than Si-IGBT; at the same time, Si-IGBT usually integrates a fast recovery diode (FRD), which has reverse recovery current and tail current when it is turned off, which limits its switching speed and causes large turn-off losses, while SiC-IGBT MOSFET is a unipolar device, like a rigid switch, there is no tail current; and the carrier mobility of SiC is about 3 times that of Si, which can provide faster switching speed to reduce switching losses. Combined with the research data of Infineon, the turn-off loss of SiC MOS is about 20% of that of Si-IGBT at a junction temperature of 25 °C; at a junction temperature of 175 °C, the turn-off loss of SiC-MOS is only 10% of that of Si-IGBT. %.

1.4 Help new energy vehicles achieve lightweight

Lightweight is the unremitting pursuit of OEMs. Due to the high carrier mobility of SiC material, it can provide higher current density, and the package size is smaller at the same power level. Taking IPM as an example, the size of SiC power modules can be reduced to silicon 2/3 to 1/3 of the power module[3]. SiC can realize high-frequency switching, reduce the use of filters and passive devices such as transformers, capacitors, inductors, etc., thereby reducing the system system and weight; SiC has a wide band gap and good thermal conductivity, which can make the device work in relatively In high ambient temperature, the volume of the radiator can be reduced; at the same time, SiC can reduce switching and conduction losses, improve system efficiency, and reduce battery capacity within the same battery life range, contributing to vehicle weight reduction. Taking the SiC inverter designed by ROHM as an example, after using the full SiC module, the size of the main inverter is reduced by 43% and the weight is reduced by 6 kg (see Figure 2).

  

Application status and introduction path of silicon carbide in new energy vehicles

Figure 2 Source of revenue from the use of SiC products in motor controllers: ROHM Corporation

2 Application status

2.1 Related companies are accelerating their layout

Since Tesla launched the Model 3 and used an inverter with 24 SiCMOSFETs as power modules for the first time, this new type of semiconductor material has received more and more attention, and OEMs and Tier 1 have actively introduced SiC power semiconductors. It is understood that BYD, BAIC New Energy, Geely Automobile, Shanghai Volkswagen, and Nissan use SiC devices in OBC and DC-DC in some of their models; BYD, Tesla Shanghai Factory, Yutong Bus, and Geely Automobile use SiC devices in motor controllers. SiC devices are used in SiC; traditional car companies Jianghuai Automobile, Hongqi, Hyundai, Honda, BMW, Audi and new car manufacturers such as Weilai, Xiaopeng, Ideal and other companies are about to use SiC in their main drive inverters. In addition, a number of component suppliers have also released plans to develop and mass-produce SiC electric drive systems, such as foreign Bosch, Delphi, ZF, and Valeo. Typical domestic companies include Jingjin Electric and Shanghai Electric Drive. , Vitesco Technology, etc. (Figure 3).

  Application status and introduction path of silicon carbide in new energy vehicles

Figure 3 The introduction of SiC by OEMs and tier1 (some companies) Source: self-organized

2.2 Market penetration is still not high

The application prospects of SiC chips in the field of new energy vehicles are widely optimistic in the industry. At present, various automobile manufacturers and suppliers have begun to deploy the R&D and industrialization of SiC chips. However, from the perspective of the market share of power semiconductors, silicon-based semiconductor products are still the mainstream in the field of new energy vehicles, and the application of SiC chips has not yet been popularized.According to Yole’s forecast, the penetration rate of SiC power Electronic devices in power devices will be 9% in 2024 (as shown in Figure 4), and the market share of SiC chips will hardly reach the level of silicon-based semiconductors in the short term.[4]Silicon-based solutions and SiC solutions are expected to coexist for a long time in the automotive field to achieve the best price/performance ratio of the powertrain.

  

Application status and introduction path of silicon carbide in new energy vehicles

2.3 Localization Expectations Become Stronger

40% of automotive-grade chips are power semiconductors, and the average value of a single vehicle is around $300. Such chips are higher than industrial-grade and consumer-grade semiconductors in terms of environmental conditions, reliability, and durability, resulting in long development time and difficulty. Large, high technical barriers, foreign manufacturers occupy most of the market share, has become a “stuck” link in my country’s automotive industry, and the epidemic and continuous extreme weather have further aggravated the crisis of this type of chips. Since the end of 2020, the automotive industry is facing Chip outage risk. As the world’s largest producer and seller of new energy vehicles, China is deeply troubled by the shortage of automotive chips. Many domestic car companies have been hindered in production due to this, and even stopped production and reduced production. It is reported that since this year, Volkswagen, Toyota, Honda, GM, Volvo and other companies have temporarily suspended production due to chip shortages. The localization of automotive-standard chips is expected to become more intense, while domestic automotive technology is accelerating towards electrification. The degree of electrification is gradually increasing. Deepening will lead to a rise in SiC volume and price.

2.4 Cost-effectiveness and reliability are in urgent need of improvement

The bottleneck in the development of the SiC industry is mainly that the cost performance of SiC MOS products is currently relatively low. In terms of price, due to the low production efficiency of SiC substrates, the cost is much higher than that of silicon wafers, coupled with the low yield of late epitaxy, chip manufacturing and device packaging, resulting in high prices of SiC devices. According to industry forecasts, the current batch production The price is still 3 to 5 times that of silicon-based IGBTs. In terms of product performance, the gate interface control technology of high quality and low interface state in the SiC MOS manufacturing process needs to be strengthened, and the batch manufacturing technology and yield also need to be further improved. At the same time, the real landing time of SiC MOS is still very short. The chain from chip and power module design to application verification at the vehicle level has not yet been opened. Some technical indicators such as short-circuit withstand time have not been verified enough, and domestic SiC There is no data for MOS devices to be installed on the road, and indicators such as stability and lifespan of SiC MOS in the automotive field still need time and practice verification.

3 Import path

3.1 Import field: transition from OBC import to motor controller

SiC power devices are mainly used in controllers, OBCs (on-board chargers) and DC-DC on-board power converters. Among them, power modules for motor controllers are the automotive SiC products with the largest growth space, and are expected to account for 10% of the SiC chip market. around 50%.From the perspective of the introduction sequence, many foreign companies have begun to use SiC Schottky barrier diodes and MOS tubes on OBCs in 2018. The market penetration of SiC in OBC and DC-DC in the field of automotive power supplies has gradually increased. Through these The application of the scene drives the technology maturity and cost reduction of SiC products, and then penetrates into motor controllers with higher reliability requirements. It is expected that the substantive application of SiC MOS tubes will not appear until 2022.[5-6].

  

Application status and introduction path of silicon carbide in new energy vehicles

3.2 Introduced models: long-range electric vehicles are the first to be introduced

The increase in cruising range will help drive the growth of electric vehicle sales. New energy vehicle companies generally rely on increasing battery capacity to increase cruising range. However, limited by battery technology and cost, it is difficult for new energy vehicle companies to significantly improve battery life through this method. The introduction of SiC technology in motor controllers has become an effective path, which has accelerated the penetration of SiC in the long-life new energy vehicle market. It is predicted that the penetration rate of SiC in the motor controller with a cruising range of more than 500 km is expected to reach 100% by 2024; the motor controller with a cruising range (400-500) km is expected to start using SiC in 2023, and the overall penetration rate is 40% around; the motor controllers of models with a cruising range of less than 400 km will use SiC after 2025, and the overall penetration rate will be less than 10%[3](see Figure 6).

  

Application status and introduction path of silicon carbide in new energy vehicles

3.3 Import time: It is expected to break out after 2025

With the improvement of the cost performance and reliability of SiC products, the penetration rate of SiC products has steadily increased. Some domestic and foreign car companies have begun to introduce SiC products into motor controllers. Among them, Tesla’s Model 3 uses SiC MOSFET-based power Control module; BYD’s “Han” is also equipped with a SiC MOSFET power control module. At present, almost all new energy vehicle companies have included the development of SiC motor controllers in the development schedule of new projects, and more and more car manufacturers will apply SiC modules. From the perspective of the global market, it is estimated that 2025 will become a flashpoint for SiC in the new energy vehicle market, and the supply of SiC may enter a stage of overall shortage.

  

Application status and introduction path of silicon carbide in new energy vehicles

3.4 Product introduction: transition from discrete devices to full SiC modules

SiC power devices include diodes and transistors. Diodes are usually used as discrete devices, and can also be used in hybrid modules or full SiC modules; transistors are also used as discrete devices or in full SiC modules.[4]. At present, the SiC power device market is still dominated by discrete devices. Diode products have been industrialized and commercialized on a large scale. Hybrid modules have also penetrated into some applications. Discrete transistors and full SiC are still being further developed and actively promoted. The development and promotion of full SiC modules is expected to take longer, but the market for full SiC modules will be larger (see Figure 8).

  

Application status and introduction path of silicon carbide in new energy vehicles

Figure 8 Source of SiC production type: Power SiC 2019: Materials, Devices and Applications

references:

  [1] Wide-bandgap semiconductors open a new chapter for new energy vehicles[N/OL].China Electronic News,[2021-6-28].https://baijiahao.baidu.com/s?id=170381625775841.

  [2] Yole Développement. Power SiC 2019: Materials, Devices and Applications[R/OL].[2019-7-21].https://www.sohu.com/a/328251230_256868.

  [3] material depth.The application prospect of domestic new energy vehicles is clear, and the supply of SiC effective production capacity is insufficient[R/OL].[2021-8-

  17].http://www.casmita.com/news/202108/17/5716.html.

  [4] Yole Développement. Power SiC 2019: Materials, Devices and Applications[R/OL].[2019-9-17].http://www.ncap-cn.com/news/report/2019/2156.html.

  [5] Xiao Xi.Xingyan|King of Power——Silicon Carbide[R/ O L ] . Xinxi Capital,[2019-09-30]. Https://mp.weixin.qq.com/s?src=11&timestamp=1632628844&ver=3337&signature=AEuEP2MtGnXopob-4retNUQMe-HjCVrb7XeRM4-p6MomHfOWAPN5YTN21NKx0nxr5xKTCvkZs61J4l6hxqhRynHhuzPoDfV2N5gvSR1pFuXE6ea7MgD38Jr8tx07GYiG&new=1.

  [6] The third-generation semiconductor joint innovation incubation center. The magic weapon for automotive electrification – silicon carbide (SiC)[R/OL]. Semiconductor materials and process equipment,[2021-1-28].https:? //mp.weixin.qq.com/s src = 11 & timestamp = 1632628874 & ver = 3337 & signature = 0mxm6mzHYjmZbjeUc5MGhNcYE2abEzmAzNxQmdmMJ4iO1ZYIqIChB2SZAx0q5l1PWNODIHAH7k6QyCSGBJ-zilOIH7ZBtUXowbXMjhHHG0Rgfto10lx6moLehuYsZl4n & new = 1.

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